DE2428689A1 - TREAD MIXTURE - Google Patents

Description

BASF Aktiengesellschaft

Our reference: O.Z. JO 594 Mu / MK

67OO Ludwigshafen, June 7, 1974

Treadmill

Tread compounds for vehicle tires have special properties to have; In particular, adhesion and abrasion resistance as well as resistance to aging (especially in the heat) are load-bearing, constantly improved properties.

The technology of manufacturing tires and their components is described many times; it is e.g. on Boström, Handbuch der Kautschuktechnologie as well as Kleemann, Introduction to the Recipe development of the rubber industry, referenced.

Now the task arises, especially after vehicle tires with mechanical adhesion aids, so-called spikes or the like, turn out to be have proven disadvantageous in many respects to find rubber-based tread compounds that are on wet or icy surfaces or snow-covered roads have good adhesive properties without the previous advances in tire technology being lost again will.

Tread compounds with improved adhesion are already known on a wet surface; e.g. polyalkylene glycols are already being tried as additives; however, these have the disadvantage of being water-soluble and are washed out of the treads over time.

Mixtures in which the usual filler carbon black is wholly or partially replaced by active silica (aerogels) can also be used tried. However, tires with this filler have a reduced service life.

It has now been found that the treads for vehicle tires have a Significantly improved adhesion on roadways of practically all surface properties, if they are in addition to the usual Components, i.e. natural or synthetic rubbers, active

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ven and other fillers, stabilizers and optionally other ingredients have a content of 2 to 25 %> in particular 2 to 15 % (based on the weight of the rubber portion) of a polyisobutylene with an average molecular weight measured viscometrically - from 30,000 to 200,000.

These tread mixtures are particularly advantageously obtained by mixing the polyisobutylene in the form of a premix (Masterbatch) mixed with the usual components with carbon black. In this case, it is appropriate to use polyisobutylene with carbon black in a proportion premixed from about 1: 3 to 3: 1. It is also possible to use polyisobutylene with approximately equal parts, i.e. likewise approximately 1: 3 to 3: 1 with natural rubber or a synthetic rubber, e.g. the commonly used styrene-butadiene rubbers (SBR). However, it is also possible to add polyisobutylene directly to the rubber mixture (for example in a kneader or rolling mill). The lower molecular weight of the polyisobutylene generally means easier miscibility; it will therefore polyisobutylenes with a molecular weight of about 30,000 to 100,000 are preferably used.

Notwithstanding certain problems posed by the use of active silica as a tread component, the use of mixtures of carbon black and silica can in some cases instead of carbon black, e.g. in a ratio of 20:80 to 80:20.

To distinguish it from previous similar attempts, it should be said that US Pat. Nos. 2,160,995, 2,160,997 and 2,220,363 are known is to add low molecular weight polyisobutylenes (as plasticizers) to tread compounds. These low molecular weight polyisobutylenes are, however, of no value in improving the grip of tires on wet surfaces. Also not related to the present invention the proposal of GB-PS 7 ^ 3 979 »has the static friction of So-called crepe sole rubbers improve by adding the raw rubber mixture mixed with short fibers and these for better connection with the raw rubber with a coating of a 'low molecular weight polyisobutylene provides.

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- 3 - ο.ζ. 30th

Incidentally, the occasional mention of polyisobutylene as rubber-elastic substance or optionally also as a mixture component for rubbers (as in Ulimann, Encyklopadie der technischen Chemie, keyword polyisobutylene) at least for their manufacture of abrasion-resistant and adhesive tread compounds so far had no consequences.

Polyisobutylenes according to the invention are the cationic polymers brought to the polymerization of isobutylene, such as the products obtained at temperatures from -120 to -90 ⁰ C in the presence of liquid ethylene as solvent and boron trifluoride or its complexes as the catalyst.

Polyisobutylenes of the type mentioned are, for example, under the trade name

^v 'Oppanol (especially with the type designations B 50, B 100 and B 150) available.

As rubbers (elastomers), which are suitable for tread compounds in the Examples which are suitable for the purposes of the invention are: natural rubber (NR), optionally oil-extended (OENR), styrene-butadiene rubber (SBR) if necessary oil-extended (OESBR), cis-polybutadiene (BR), cis-polyisoprene (IR); depending on the intended use, e.g. for treads on car, industrial vehicle or truck tire treads different base mixes are used.

Active fillers in the context of the invention include, for example, carbon blacks, such as HAP (high abrasion furnace), ISAF (inmediate super abrasion furnace), SAF (super abrasion furnace) and similar carbon blacks as well as silicas into consideration; Silicas are expediently used together with so-called activators, e.g. of the certain type sulfur-containing organosilanes are used.

As an aging agent that is related to the present Invention particularly suitable and in particular the properties of the polyisobutylene rubber mixtures obtained have a favorable effect are to be mentioned: p-phenylenediamine (derivatives), phenylnaphthylamine, Phenol (derivatives), quinoline (derivatives).

S098S1 / 0251

ο.Z. J) Q 594

Relevant anti-aging agents are e.g. in Voigt, The stabilization of plastics against light and heat (Springer-Verlag, 1966, Berlin) dealt with in detail. Reference is also made in this context to the aforementioned book by Kleemann, which also deals with the use of other rubber auxiliaries.

Test facility

The measurements were made on vulcanized rubber disks 6 mm thick and 60 mm in diameter. As a base, various practice matched road surfaces in the form of plates at room temperature, -as well as from 0 to -25 ⁰ C. The measuring device is shown schematically in the figure.

Herein mean:

Ia = rubber sample 5 = hygrometer

Ib = layer of ice 6 a, b = force measuring ring

Ic = road surface 6c = oscilloscope

2 = load weight 7 = threaded spindle

3 a, b, c = temperature measurement 8 = climate cell

4 = fan

Normal forces of 50, 100 and 150 N acted on the rubber disks. The disks were tightened by turning the threaded spindle evenly moves smoothly at low sliding speed. In the train system A straight force measuring ring was switched on, the deformation of which was measured inductively and measured on an oscilloscope for the frictional force was read.

The coefficient of sliding friction (coefficient of friction) is calculated according to the equation

Mean:

R friction force (Newton)

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O.z. 30 594

N = m * g = normal force (Newton)

Mass of the load in kg

Gravitational acceleration in - "

example 1

Test mixture (car tread) A. 40 B. 40 C. 40 Cf. 60 60 60 40 Rubber (Buna sleeve 1500) 50 50 50 60 Rubber (Buna GB 11) 10 10 10 50 Carbon black N 220 1 1 1 10 Naphthenic plasticizer 1 1 1 1 Anti-aging agent 4010 NA 3 ■ 3 3 1 Phenyl-ß-naphthylamine 1.5 1.5 1.5 3 zinc oxide 1.8 1.8 1.8 1.5 Stearic acid 1.2 1.2 1.2 1.8 sulfur 0.2 0.2 0.2 1.2 Vulkacit CZ 5 10 30th 0.2 Vulkacit D - Polyisobutylene (Oppanol B 100) Physical data 67 61 60 (VuIk. 20 min./151 ° C) 133 122 138 80 Module (300 % kp / cm ² ) - 462 47O 540 138 Strength (kp / cm) 57 55 55 440 Elongation (%) 62 61 71 59 Hardness (° Shore A) 62 Standard abrasion (mm) 1.25 1.51 1.40 Results (coefficient of friction) 1.32 1.59 1.52 0.56 Asphalt dry 50 N 1.24 1.56 1.53 0.56 Asphalt dry 100 N 1.11 0.99 1.11 0.63 Asphalt dry 15O N 1.11 1.05 1.05 0.83 Wet asphalt 50 N 1.11 1.24 1.18 0.70 Asphalt wet 100 N 1.51 1.65 1.51 0.65 Wet asphalt 150 N 1.44 1.52 1.44 1.11 Basalt dry 50 N- 0.97 Basalt dry .100 N

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Basalt dry 15O N

Basalt wet 50 N

Basalt wet 100 N

Basalt wet 150 N

1.29 1.53 1.43 0.83 1.26 1.12 0.98 0.70 1.24 1.18 1.05 0.76 1.20 1.20 1.20 0.82

Example 2

Test mixture (truck tread, free of soot)

Rubber (Smooked Sheets RSSl) Rubber (Buna CB) Silica

Silica activator (Degussa X 50) polyisobutylene (Oppanol B 50) Koresin

zinc oxide

Stearic acid

Naphthenic plasticizer phenyl-ß-naphthylamine Phenyl-Qt-naphthylamine Anti-aging agent 4010 NA sulfur

Vulkacit CZ

Vulkacit D

5 B. 40 5 Cf. 40 8th 60 8th 40 60 75 65 75 60 65 14th 65 14th 3 10 3 14th 10 5 - - 5 - VJl 2 5 2 12th 2 12th 1 12th 1 0, 1 ο, 0, 0.5 ο, 1, 0.8 ι, 1 1.75 1 ι, 1 ι, 1.3

Physical data (VuIk. 40 min./151 ⁰ C) Module (300 % kp / cm ² ) Strength (kp / cm ³ ) Elongation {%)
Hardness (° Shore A) Standard abrasion (mnr)

Results (coefficient of friction) load 50 N asphalt dry asphalt wet
Asphalt ice
Asphalt ice

22 ° C

22 ° C

- 5 ° C

-10 ° C

53 43 75 142 133 137 638 692 474 67 64 68 67 64 55

0.87 1.25 0.77 0.75 0.96 0, -66 0.07 0.08 0.06 0.12 0.12 0.08

509851/0251

Asphalt ice asphalt ice

Example 3

-15 ⁰ C -2O ⁰ C

ο.ζ. 30th

ο, 12th ο, 20th 0, 08 ο, 43 ο, 55 0, 32

Test mixture (truck tread)

Rubber (Smooked Sheets RSSl) Rubber (Buna CB) Carbon black N 220 Silicic acid Silica activator (Degussa X 50) zinc oxide Stearic acid naphthenic plasticizer phenyl-ß-naphthylamine Anti-aging agent 4010 NA sulfur Vulkacit CZ Vulkacit D polyisobutylene (Oppanol B 50)

Physical data (VuIk. 30 min./151 ° C) Module (300 % kp / cm ² ) Strength (kp / cnr) Elongation (%) Hardness (° Shore A) Standard abrasion (mnr)

Cf. 40 40 60 60 35 35 27 27 6th 6th 5 5 CVl 2 12th 12th 1.5 1.5 0.8 0.8 1.75 1.75 1 1 1 1 10

58 67 161 178 600 590 53 57 65 62

Results ■ (coefficient of friction) smooth N 22 ° C Load 50 smooth dry 22 ° C basalt smooth wet - 5 ° C basalt smooth icy -10 ⁰ C basalt smooth icy -15 ° C basalt smooth icy -20 ⁰ C basalt smooth icy -25 ° C basalt icy. basalt

2.00 1.80 1.15 1.09 0.50 0.51 0.57 0.56 0, -85 • 0.77 0.94 0.89 0.97 0.89

509851/025

Claims (2)

ο, ζ ο 30 patent claims 1. Use of a polyisobutylene with an average molecular weight - determined viscometrically - of 30,000 to 200,000 in an amount of 2 to 25 % as a component of a tread mixture for vehicle tires, the amount being based on the rubber content. 2. A method for adding polyisobutylene to a tread mixture according to claim 1, characterized in that the polyisobutylene is added to the other components in the form of a premix with carbon black in a ratio of 1: 3 to 3: 1. BASF Aktiengesellschaft drawing 509851/0251